The invention is directed towards polymers of geminally disubstituted olefins, carbon monoxide and ethylene. The invention also encompasses a method for producing the geminally disubstituted olefin-carbon monoxide-ethylene polymers using free radical polymerization.
Terpolymers of ethylene-carbon monoxide-X (xe2x80x9cExe2x80x94COxe2x80x94Xxe2x80x9d), where X is third monomer, such as vinyl acetate or methyl methacrylate, are generally made from ethylene, carbon monoxide (xe2x80x9cCOxe2x80x9d), and vinyl acetate or methyl methacrylate feeds. These polymers are prepared using free radical initiators at high pressures and temperatures. Furthermore, these polymers are random, which are generally difficult to make using organometallic catalysts. The Exe2x80x94COxe2x80x94X polymers formed from free radical polymerization are useful as polyvinyl chloride (xe2x80x9cPVCxe2x80x9d) modifiers and degradable films.
Geminally disubstituted olefin monomers, such as isobutylene, are known not to be readily polymerizable by free radical polymerization mechanisms. Instead, such disubstituted a-olefins are typically polymerized and copolymerized by cationic or carbocationic polymerization with Lewis acid catalyst systems known to initiate the formation of carbocations.
PVC is one of the most economic, versatile and useful commodity polymers for a wide variety of applications. Presently, PVC is the second largest thermoplastic resin manufactured behind polyolefins, with a world-wide capacity of approximately 31 millions tons. The exceptional versatility of PVC is partially due to its ability to form stable solutions of wide percentage composition with a variety of plasticizers and additives.
Plasticizers are added to plastics to improve flow and, therefore, processability and flexibility, and to reduce the brittleness of the product. This is achieved by lowering the glass transition temperature (Tg) below room temperature, thus achieving a change in properties from that of a hard, brittle, glasslike solid to that of a soft, flexible, tough material. There are presently about 450 different plasticizers produced worldwide, although only about 50 of these are classified as commercially important. Approximately 90% of these products are used in the production of plasticized or flexible PVC.
More than 95% of these plasticizers are very low molecular weight ( less than 500) monomeric esters. One of the problems with low molecular weight plasticizers is their tendency to volatilize during the various processing steps in manufacturing flexible PVC articles. Volatilization losses in end uses can be even greater. Also, plasticizers leave by volatilization, migration, and extraction. Plasticizers can migrate into other materials, such as other PVC, polystyrene, acrylics and ABS, or even some nitrocellulose based paint finishes. It is desirable to have products with lower volatility, less migration and more extraction resistance. Using high molecular weight polymers minimizes the volatility problems.
In one embodiment, the instant invention provides geminally disubstituted olefin-carbon monoxide-ethylene polymers. These polymers may be used as effective plasticizers in polyvinyl chloride compositions.
In another embodiment, the invention is a composition comprising a geminally disubstituted olefin-carbon monoxide-ethylene-X polymer, wherein monomer X is a free radical polymerizable monomer or mixtures of monomers. Monomer X is selected from C3 to C30 alpha-olefins, C3 to C30 internal olefins, styrene, styrene derivatives, unsaturated mono- and dicarboxylic acids of 3-20 carbon atoms, esters of such unsaturated mono- and dicarboxylic acids, vinyl esters of saturated carboxylic acids wherein the acid group has 1-18 carbon atoms, vinyl alkyl ethers wherein the alkyl group has 1-18 carbon atoms, halogenated ethylene derivatives, methyl vinyl ketone, 1-vinylpyrrolidone, acrylonitrile, acrylamide, acrolein, allyl alcohol, allyl chloride, allyl acetate, and mixtures thereof. The mixtures of monomer X can also be raffinate I or raffinate II.
In yet another embodiment, the invention is a polymerization method comprising reacting a geminally disubstituted olefin feed, a carbon monoxide feed and an ethylene feed under free radical polymerization conditions to form a geminally disubstituted olefin-carbon monoxide-ethylene polymer.
In still another embodiment, the invention is a polymerization method comprising reacting a geminally disubstituted olefin feed, a carbon monoxide feed, an ethylene feed and a feed containing monomer X under free radical polymerization conditions to form a geminally disubstituted olefin-carbon monoxide-ethylene-X polymer, wherein monomer X is a free radical polymerizable monomer.
Another embodiment of the present invention is a PVC resin composition comprising polyvinyl chloride and a plasticizer selected from either: i) a geminally disubstituted olefin-carbon monoxide-ethylene polymer; ii) a geminally disubstituted olefin-carbon monoxide-ethylene-X polymer; or iii) mixtures thereof, wherein said monomer X comprises a free radical polymerizable monomer, and further wherein said polymers are synthesized at free radical polymerization conditions.
The instant invention is further directed to a method for preparing such a PVC resin by blending PVC with either: i) a geminally disubstituted olefin-carbon monoxide-ethylene polymer; ii) a geminally disubstituted olefin-carbon monoxide-ethylene-X polymer; or iii) mixtures thereof.
These and other features, aspects and advantages of the present invention will become better understood with regard to the following description and appended claims.